In recent years, there has been developed, as a suspension system for a vehicle, a so-called electromagnetic suspension system including an electromagnetic actuator configured to generate a force by which a body and a wheel of a vehicle are moved toward and away from each other in a vertical direction. For instance, the following Patent Document 1 discloses such an electromagnetic suspension system. The disclosed suspension system is expected to be a high-performance suspension system in view of an advantage that it is possible to easily realize a suspension characteristic based on a so-called skyhook theory.    Patent Document 1 JP-A-2003-42224